01 / 07
1 · Same city, different heat

THE CITY THAT STORES SUNLIGHT

Two kids leave school in Los Angeles and check the forecast.

One walks beneath trees. The other passes a sunny parking lot. Their walks feel nothing alike.

What does the forecast miss?
SHADED WALK
SUNNY WALK
PHEW!
2 · The heat clues

What makes one block feel hotter?

A weather app gives one temperature for a big area. But nearby blocks can feel different because of what covers the ground, how much shade and greenery they have, and whether people and machines are adding heat.

Look for four clues: ground cover, plant cover, shade, and extra heat from traffic.

Science: UCLA Fielding School of Public Health · why some L.A. neighborhoods run hotter

4 CLUES TO SPOT
A large paved parking lot at Los Angeles City College
01WHAT COVERS THE GROUND?

Blacktop, concrete, and dark roofs soak up sunlight and can stay warm later.

A Los Angeles street lined with many large trees and lots of plant cover
02HOW MANY PLANTS ARE THERE?

Trees and plants help cool the air. Greener blocks usually feel cooler than bare ones.

A playground with a canopy-style shade structure overhead
03HOW MUCH SHADE IS THERE?

Shade can come from trees, shade sails, canopies, bus shelters, or awnings. More shade helps people stay cooler.

Heavy traffic on the 101 freeway in Los Angeles
04WHAT ADDS EXTRA HEAT?

Cars and buses give off heat, so busy roads can feel hotter than quieter streets.

Photo credits

LACC parking lot: Downtowngal, CC BY-SA 4.0; Hancock Park trees: Downtowngal, CC BY-SA 4.0; Canopied playground: Philipp Michel Reichold, CC BY-SA 4.0; 101 traffic: Buhin, public domain. Photos cropped to fit cards.

3 · Uneven protection

Who gets the cooler neighborhoods?

Not every part of Los Angeles heats up the same way. Wealthier neighborhoods often have more trees, larger lots, and more shade, while poorer neighborhoods nearby often have more pavement and less cooling cover.

The pattern: cooler colors on the map show less heat stress. You can see cooler conditions around places like Santa Monica, Beverly Hills, Bel Air, and Encino compared with many nearby lower-income neighborhoods.
Blue and yellow areas are cooler. Orange and red areas are hotter.

Map reference: regional heat map provided by user

WHO STAYS COOLER?
Sharpened Los Angeles heat map showing cooler coastal and wealthier hillside areas and hotter inland neighborhoods
Cooler coastal and wealthier areas often have more trees, more shade, and less heat buildup.
Big idea: Heat is not spread evenly. Richer areas often have more protection from heat, while poorer neighborhoods nearby face hotter conditions.
4 · Heat & health

Heat can stop the game.

Shade can be the difference between keeping active and having to sit out.

Illustration of a child feeling sick from heat, sweating heavily under a hot sun
DEHYDRATIONHEADACHEDIZZINESSHEAT EXHAUSTION
Heat stroke is a medical emergency. Extreme heat can become dangerous when the body can no longer cool itself.
Compare the shaded court with the sunny court.

Health context: UCLA Fielding School of Public Health

SHADED COURT
FULL SUN
STILL PLAYINGTOO HOT
SHADE KEEPS PLAY POSSIBLEThe player can keep moving without direct sun beating down.
HEAT STOPS THE GAMEThe exposed player has to sit down and cool off. Too much heat can lead to dehydration, dizziness, or heat exhaustion.
5 · Nature cools

This little tree is just getting started.

Planting it is only the beginning. If it gets enough water and care, it can slowly change the block around it.

TodayIts roots begin settling into the soil and taking up water.
As it growsMore leaves mean more shade—and some of the water moving through the tree returns to the air.
Years from nowA bigger canopy can keep people and pavement out of direct sun.

One small tree will not cool a neighborhood overnight. But many healthy trees, given time, can change how a whole block feels.

Photo: provided by user · Learn more: U.S. EPA · UCLA Luskin

FROM SAPLING TO SHADE
People planting and watering a young tree in a neighborhood lawn
Water it now. Shade comes later.Growing a cooler neighborhood takes time—and care.
Conclusion

A cooler city is something we can build.

Heat is not spread evenly across Los Angeles. Trees, shade, plants, and smarter surfaces can make a real difference in how hot a neighborhood feels. As climate change raises temperatures, this problem can become even worse.

The big idea: where we add shade and greenery matters—especially in the places that need cooling most.

Urban heat is an environmental problem, but it is also a design problem.

Shaded tree-lined neighborhood street in Los Angeles showing how canopy can help keep a city cooler
Cooler neighborhoods are possible.Plant more trees, add more shade, and design streets for people—not just pavement.